The Boardwalk is a fun place to stay and your kids will love it. There is an oversized "sofa" as you enter the lobby that your kids might like taking a picture in (assuming that it's still there).
There are also various spots along the Boardwalk itself where your kids can buy "fish" food (although the ducks tend to get to it first) and they can feed the fish (or ducks). My daughters LOVE to feed the fish/ducks and watch them race for the food.
I'm sure that they can get their faces painted at booths there on the boardwalk and, of course, there are always the surreys.
One of my favorite stops is the bakery (I like to get the rice crispy treats). I also enjoy the candy shop.
You can also walk over to Fantasia Miniature Golf Course for a round or two of minuature golf...or just walk over and through the Swan, Dolphin, Yacht and/or Beach Clubs.
You might even catch a wedding at Sea Breaze Point on the boardwalk (that's where we were married).
And right on past Sea Breaze Point is a bridge and off to the right of the bridge is the walkway to Epcot's International Gateway.
You can also reserve an Illuminations cruise and they will pick you and your party up right there at the boat dock at the boardwalk. (We took our wedding party on an Illuminations cruise right after our ceremony).
And I've just scratched the surface....As you can see, you'll have plenty to do and will have to work hard to NOT have a good time...